Source: Science Daily, May 2018

Despite the declining death rates for many individual cancer types, mortality for a few cancers has stabilized or even increased. One of these is melanoma due to its ability, in later stages, to spread to other parts of the body. Melanoma is considered metastatic — also called Stage IV melanoma — when the cancer cells have spread through the lymph nodes to distant sites in the body, the most often affected being liver, lungs, bones and brain.
Often primary melanomas grow and spread horizontally on the top layer of the skin before penetrating deeper into the layers of the dermis where they can reach the lymph and blood vessels. Lymphatic invasion and lymph node metastasis correlate with poor clinical outcome in melanoma.
In addition to providing a direct route for dissemination, the lymph vessels have been proposed to directly modulate the metastatic process through mechanisms that have remained elusive.read the original full article